Question

我使用hotchemi PermissionsDispatcher来检查权限。它适用于API＆gt; = 23.但是当我尝试在具有API 16的设备上使用相同的代码时，我得到了一个FATAL EXCEPTION java.lang.StackOverflowError。当我在生成的类showCameraWithCheck()

中调用MainActivityPermissionsDispatcher时，错误会增加

我深入研究了PermissionsDispatcher库生成的类MainActivityPermissionsDispatcher，并找到了Stack Overflow发生的原因。当我致电MainActivityPermissionsDispatcher.showCameraWithCheck(this);时，它会在生成的MainActivityPermissionsDispatcher：

中转到此方法

static void showCameraWithCheck(MainActivity target) {
if (PermissionUtils.hasSelfPermissions(target, PERMISSION_SHOWCAMERA)) {
  target.showCamera();
} else {
  if (PermissionUtils.shouldShowRequestPermissionRationale(target, PERMISSION_SHOWCAMERA)) {
    target.showRationaleForCamera(new ShowCameraPermissionRequest(target));
  } else {
    ActivityCompat.requestPermissions(target, PERMISSION_SHOWCAMERA, REQUEST_SHOWCAMERA);
  }
}

}

事情是PermissionUtils.hasSelfPermissions(target, PERMISSION_SHOWCAMERA)总是如此，所以它调用target.showCamera()这是我的方法，它调用MainActivityPermissionsDispatcher.showCameraWithCheck(this);所以它进入无端循环....我猜hasSelfPermissions() 1}}方法检查它是否具有运行时权限（API＆gt; = 23）或旧样式权限（＆lt; API 23）。

E / AndroidRuntime：致命异常：主要 java.lang.StackOverflowError的在android.os.Parcel.readException（Parcel.java:1376）在 android.app.ActivityManagerProxy.checkPermission（ActivityManagerNative.java:2874）在android.app.ContextImpl.checkPermission（ContextImpl.java:1285）在 android.content.ContextWrapper.checkPermission（ContextWrapper.java:421）在 android.support.v4.content.PermissionChecker.checkPermission（PermissionChecker.java:89）在 android.support.v4.content.PermissionChecker.checkSelfPermission（PermissionChecker.java:125）在 permissions.dispatcher.PermissionUtils.hasSelfPermissions（PermissionUtils.java:73）在 com.example.android.permissionsdispatcherapp.MainActivityPermissionsDispatcher.showCameraWithCheck（MainActivityPermissionsDispatcher.java:20）在 com.example.android.permissionsdispatcherapp.MainActivity.showCamera（MainActivity.java:52） ......................

@RuntimePermissions
public class MainActivity extends AppCompatActivity {
private static String LOG_TAG = MainActivity.class.getSimpleName();

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    try {

        Button btnShowCamera = (Button) findViewById(R.id.btn_show_camera);
        btnShowCamera.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Log.i(LOG_TAG, "Show camera button pressed.");
                showCamera();
            }

        });
    } catch (Exception e) {
        e.printStackTrace();
    }
}

@NeedsPermission(Manifest.permission.CAMERA)
void showCamera() {
    // NOTE: delegate the permission handling to generated method
    // ERROR
    MainActivityPermissionsDispatcher.showCameraWithCheck(this);
}

@Override
public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
    super.onRequestPermissionsResult(requestCode, permissions, grantResults);
    // NOTE: delegate the permission handling to generated method
    MainActivityPermissionsDispatcher.onRequestPermissionsResult(this, requestCode, grantResults);
}

@OnPermissionDenied(Manifest.permission.CAMERA)
void onCameraDenied() {
    // NOTE: Deal with a denied permission, e.g. by showing specific UI
    // or disabling certain functionality
    Toast.makeText(this, R.string.permission_camera_denied, Toast.LENGTH_LONG).show();
}

@OnNeverAskAgain(Manifest.permission.CAMERA)
void onCameraNeverAskAgain() {
    Toast.makeText(this, R.string.permission_camera_never_askagain, Toast.LENGTH_LONG).show();
}

@OnShowRationale(Manifest.permission.CAMERA)
void showRationaleForCamera(PermissionRequest request) {
    // NOTE: Show a rationale to explain why the permission is needed, e.g. with a dialog.
    // Call proceed() or cancel() on the provided PermissionRequest to continue or abort
    showRationaleDialog(R.string.permission_camera_rationale, request);
}

private void showRationaleDialog(@StringRes int messageResId, final PermissionRequest request) {
    new AlertDialog.Builder(this)
            .setPositiveButton(R.string.button_allow, new DialogInterface.OnClickListener() {
                @Override
                public void onClick(@NonNull DialogInterface dialog, int which) {
                    request.proceed();
                }
            })
            .setNegativeButton(R.string.button_deny, new DialogInterface.OnClickListener() {
                @Override
                public void onClick(@NonNull DialogInterface dialog, int which) {
                    request.cancel();
                }
            })
            .setCancelable(false)
            .setMessage(messageResId)
            .show();
}
}

enter code here

Answer 1

找到了方法。我的代码错了。它不需要调用showCamera()方法，因为生成的类MainActivityPermissionsDispatcher已经这样做了。由于API 16没有运行时权限，因此它以无结束循环结束。

这是修复：

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    try {
            Button btnShowCamera = (Button) findViewById(R.id.btn_show_camera);
            btnShowCamera.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
            Log.i(LOG_TAG, "Show camera button pressed.");
            askForPermission();
            }

        });
    } catch (Exception e) {
        e.printStackTrace();
    }
}

void askForPermission() {
    MainActivityPermissionsDispatcher.showCameraWithCheck(this);
}

@NeedsPermission(Manifest.permission.CAMERA)
void showCamera() {
    Toast.makeText(this, "Showing camera", Toast.LENGTH_LONG).show();
}

具有API＆lt;的Android PermissionsDispatcher 23

1 个答案: